Supercharged Jeep boost tuning

[tjhenne]

I have 2013 3.6L Jeep with a magnuson blower 6psi pulley. From the tables at 3.5 volts from the throttle FA power enrich mode is active. FA power enrich + FA stoich = final commanded AFR. My real problem, power enrichment is being enabled based upon at throttle position, not a MAP value. (or is it and I don't see a table for it)

I know how to correct the VE table but what I really need is to get into PE mode without having to floor it. I could obviously lower the pedal position required to enter PE mode and then adjust the FA power enrich, but that just doesn't seem appropriate and I would be running in open loop most of the time in the end.

I am skewed from GEN III and IV tuning but I am used to tuning boost from a certain MAP pressure or MAF frequency

Help? Thanks in advance!

[ElecTech]

No such luck here. Throttle angle only on DCX applications.

[SultanHassanMasTuning]

enable OPEN LOOP

[06300CSRT8]

Engine>Fuel>Open & Closed Loop set your Closed Loop enable temp to 376 degrees and you will be in open loop 100% of the time until you reflash with a lower temp setting.

[tjhenne]

I disabled closed loop for tuning the ve tables with my wideband so the fuel trims were not messing with me. After ve tuning was complete I put it back to closed loop so it will get feedback from the fuel trims like a normal vehicle. Is this not the way to tune this application? It seems like dodge needs a pe enrichment enabler based upon map pressure.

In the gm world I have only ran boosted cars in open loop in track applications only.

Is it possible to log maf frequency and tune it in maf only? That would eliminate the need to hack up the ve table. I just didn't see a pid for maf frequency or voltage
.
Thanks dor any assistance!

[monty007]

Is it possible to log maf frequency and tune it in maf only? That would eliminate the need to hack up the ve table. I just didn't see a pid for maf frequency or voltage
.
Thanks dor any assistance!

This car has no maf sensor

[tjhenne]

So is the consensus to run in open loop permanently when putting forced induction on?

[sut123]

I'm feeling your pain right now. I'm dealing with a small turbo and part throttle boost. While cruising around and getting into part throttle boost the O2's are fighting back and trying to run 14.4 air fuels in closed loop at quarter throttle (like they should). Problem is I can see 8 lbs at 2500 rpm if the load is right. The engine doesn't seem to detonate or even mind it but EGT's have to be through the roof and I don't want to melt it down passing over the mountains. What I planned on doing was adjusting the "Throttle WOT" table to put the engine into power enrichment sooner. I don't know if its the right way to do it but I was going to give it a shot and see what happens. I'm really not excited about running open loop all the time but I will if I have too.

[06300CSRT8]

EGTs are calculated by the PCM and are not actual readings, you can rest assured the true EGTs are not what you are seeing in the logs. Without the OS of the PCM being recalibrated on how to calculate EGTs while in boost, they will be fairly inaccurate.

How are you currently controlling boost with your setup sut? I would work on your blow off valve and wastegate setup to eliminate some more of the part throttle boost.

[06300CSRT8]

So is the consensus to run in open loop permanently when putting forced induction on?

Not at all, open loop should be used to do initial tuning and then be set to run normal. If anyone is uber worried about part throttle boost and frying pistons, there are three things you can set to be conservative. Bring your spark WOT threshold down to a lower voltage along with the fueling (throttle and pedal). I wouldn't go much lower than 2.3-2.4, though, and always have your spark come in a few .1's voltages higher.

Second, start to log and figure out what PEDAL position voltage and percent starts to see boost, and get your Pedal % Power table lined up so that half throttle by voltage and percent equates to 50% pedal position. This means you should NEVER see boost until half pedal or more. Car may feel sluggish after this setting and you can play with it, bring in some more power slowly. It becomes a personal preference, remote tuners can dial it in with some feedback easily.

Third, you should really have your FA enrichment table blended so that in the lower aircharges (or pressure ratios depending on year PCM) you should be commanding Stoich (14.7 AFR) and then interpolate to the rows you are in while under boost (say 11:1 AFR). This way when you bring your fuel open loop thresholds in earlier, you don't have a 11:1AFR at part throttle boost, maybe you want 12.5:1 at 2-3psi and 12.0 at 5 psi and 11:1 at 8psi. takes some finagling but worth it if you want to do it the right way.

Lastly, not as impactful but in your Spark Advance you have Throttle Spark tables which allow you to generically pull back timing when the throttle changes quickly (but still not into open loop). So if you go from say .75 volts (moderate cruising) and then to 2.0 volts (half throttle) you will get a few seconds of reduced timing. This can help reduce spool time and create some lag in case the throttle move was just for a quick maneuver in traffic and not looking for a full balls to the wall spool up and go. You would have to be pretty aggressive but if you limit it to the bigger voltage moves it could help.

[sut123]

SRT8, thank you for the responses and sorry about hijacking the thread.....

My setup is simple, an external wastegate with an 8lb spring and vacuum referenced on both the POV and wastegate. Clean and easy and how I want it on the jeep. Easy to fix and maintain when I am stuck in middle of nowhere and stuff starts breaking.

I made changes to the pedal position voltage and it helped a ton. Power did fall greatly like you mentioned but it didn't run up to boost immediately which controlled Air fuel at cruise. I read that making changes to the Flow Factor Min will also help control the boost at part throttle so I plan on giving that a shot tomorrow as well. Thanks again, your the man SRT8!

[tjhenne]

Thanks to all for the help. I won't be able to look at this thing until the weekend however I will post how it works out for me.

Side note, does anyone experience idle timing that is all over the place? Does the pcm control everything based upon torque request or reference?

[Mep_q8]

Just looking over your tune. Your Pedal WOT Voltage is still set at the factory settings. Change it to 3V to come on sooner. If you need to work on it, let me know, we can look at it remotely.